In ultrasonic diagnosis, how the heart beats or the fetus moves is displayed in real time by simply bringing an ultrasonic probe into contact with the body surface. Ultrasonic diagnosis is highly safe, and hence allows repetitive examination. In addition, a system in ultrasonic diagnosis is smaller in size than other diagnostic apparatuses such as an X-ray diagnostic apparatus, CT apparatus, and MRI apparatus, and hence can be moved to the bedside to be easily and conveniently used for examination. For this reason, ultrasonic diagnosis can be said to be a simple diagnostic technique.
Ultrasonic diagnostic apparatuses for performing such ultrasonic diagnosis vary in type depending on the types of functions incorporated in the ultrasonic diagnostic apparatuses. Of these ultrasonic diagnostic apparatuses, some compact apparatuses which have already been developed are small enough to be carried with one hand. Ultrasonic diagnosis is free from the influence of radiation exposure unlike diagnosis using X-rays. Therefore, such ultrasonic diagnostic apparatuses can be used in obstetrics, medical care at home, and the like.
An ultrasonic diagnostic apparatus emits, into an object, ultrasonic pulses generated from the ultrasonic transducers incorporated in an ultrasonic probe. The ultrasonic diagnostic apparatus receives reflected waves from the object tissue via the ultrasonic transducers, and generates and displays image data and the like. Using such an ultrasonic diagnostic apparatus allows an operator such as a doctor to perform image diagnosis for an object.
As an image diagnostic technique using an ultrasonic diagnostic apparatus, there is available a technique in which the operator compresses/decompresses (pressurizing/depressurizing operation) an object tissue by using the ultrasonic probe and the generated strain information (to be written as strain distribution information hereinafter) concerning the object tissue is calculated as hardness information concerning the tissue.
In order to calculate strain distribution information, such an ultrasonic diagnostic apparatus needs to detect the displacement or moving velocity of the tissue in accordance with the compression/decompression of the tissue. The displacement or moving velocity of the tissue is detected by, for example, a method of detecting the displacement of the tissue between adjacent frames based on the cross-correlation between signals (reception RF signals) received via the ultrasonic probe, a method of detecting the moving velocity of the tissue by the Doppler method, or a method combining such methods.
In this case, to properly obtain the above strain distribution information, the operator needs to compress/decompress the tissue by using the ultrasonic probe with proper strength in a proper cycle. That is, since the accuracy of strain distribution information depends on operation by the operator, it is preferable to feed back the state of compression/decompression by the operator to him/her in order to obtain proper strain distribution information.
In contrast to this, there is known a technique of presenting a waveform representing the state (strength and cycle) of compression/decompression by the operator. This allows the operator to check the state of compression/decompression by his/her operation.
However, presenting only a waveform representing the state of compression/decompression by the operator may not allow the operator to grasp the proper degree of compression/decompression. This may lead to a failure to obtain proper strain distribution information.
It is an object to provide an ultrasonic diagnostic apparatus which enables the operator to perform proper compression/decompression and a probe pressurization/depressurization information display method which can display proper compression/decompression to the operator.